DESCRIPTION (provided by investigator): Preterm delivery, intrauterine growth restriction and low birth weight are major causes of infant mortality and severe morbidity in the United States. We propose to investigate the hypothesis that maternal exposure during pregnancy to ambient air pollution (CO, NO2, O3,, PM2.5, PM10, SO2) and traffic (a significant local source of air pollution) is associated with increased risk for low birth weight (<2500 gm), preterm delivery (<37 weeks gestation) and small for gestational age birth (< 10th percentile weight for gestational age). Several studies have examined the relationships between these adverse birth outcomes and maternal exposure to ambient air pollution but results have been inconclusive. A major impediment to this research has been the large sample size needed to investigate these relationships as well as the level of personal information needed to address potential confounders and accurately estimate exposure throughout pregnancy. This study will utilize two related datasets for the same geographic area and time period: (1) an existing cohort of women (N=10,524) followed prospectively throughout pregnancy by the Yale Center for Perinatal, Pediatric and Environmental Epidemiology; and (2) birth certificate data (480,000 singleton live births in CT and MA, 2000 to 2006). The cohort data provides well characterized variables to control for all major confounders and information about each of the mothers' residences throughout pregnancy to accurately assess exposure. The birth certificate data provides the statistical power to investigate severe, less frequent outcomes (very low birth weight <1500 gm, very preterm delivery <32 weeks), and to examine the effects of air pollution and traffic among African American women, already at risk for preterm delivery and low birth weight. A comparison study will also be conducted to determine the reliability of birth certificate data for use in air pollution research. Since all exposure assessments have some limitations, we propose four methods to measure exposure to air pollutants: central site monitors; a GIS/traffic model; land use regression to measure NO2 exposure; and satellite imagery to measure PM2.5 exposure. The proposed study will have the power to estimate odds ratios of 1.15 and 1.25 in the birth certificate and cohort data, respectively. If an association is confirmed, reductions in specific types of air pollution may result in a reduction in adverse birth outcomes. PUBLIC HEALTH RELEVANCE Preterm delivery and low birth weight are major causes of infant death and disability in the United States. This study will investigate whether a mother's exposure during pregnancy to air pollution and traffic (a significant local source of air pollution) is associated with increased risk for these adverse birth outcomes. If confirmed, reductions in specific types of air pollution may reduce these major infant health problems.